Inside Earth:
Chapter 2: Earthquakes
Section 1: Earth’s Crust in Motion
Vocabulary:
Earthquake:
Shaking and trembling that results from the movement of rock under the Earth’s
surface
Stress: a force that acts on rock to change its force or volume
Shearing: stress that pushes a mass of rock in two separate directions
Tension: stress pulls on the crust, stretching rock so that it becomes thinner in the middle
Compression: stress that squeezes rock until it folds or breaks
Fault: break in Earth’s crust when flaps of Earth’s crust slips past each other
Strike-Slip Fault: created by shearing; when rocks on either side of the fault slip past each
other sideways with little up or down motion
Normal Fault: caused by tension; the fault is at an angle; one block of rock lies above the
fault while the other block lies below the fault
Reverse Fault: caused by compression; same as a normal fault but block moves in opposite
direction
Deformation: change in the volume or shape of Earth’s crust due to stress
Hanging Wall: part of the rock that is above the fault (line that splits the land)
Footwall: part of the wall that lies below the fault
hanging wall
fault
footwall
Fault Block Mountains: forms when normal faults push up a block of rock; where two
Folds: bends in rock that form when compression shortens and thickens part of Earth’s crust
Anticline: fold in rock that bends upward into an arch
Syncline: fold in rock that bends downward in the middle to form a bowl
Plateau: faults cause a large area of flat land to be pushed upward, high above sea level
Important Facts:
 Faults are breaks in the crust
 Plate Boundaries are MAJOR faults